One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You will be able to estimate when you can plant nierembergia by checking out the USDA zone info for Merrill.

Planting Calendar for Nierembergia

Frost tolerance for nierembergia:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since nierembergia require warm weather you have to wait until after the last frost has passed before you can plant them.

The earliest that you can plant nierembergia in Merrill is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant nierembergia and expect a good harvest is probably August. You probably don't want to wait any later than that or else your nierembergia may not have a chance to fully mature. Starting your nierembergia indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Merrill. You should expect an average low temperature of -30°F in the coldest months of winter.

Since the USDA zone info for Merrill may not be accurate from year to year the actual date of last frost changes from year to year. Half of the time in Merrill it frosts late in the year after May 15 so be sure to be ready to protect your nierembergia in the event of a surprise late frost.

USDA Zone Info for Merrill

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Merrill

You may be interested in your other planting guides for Merrill.